Issue with Space Invaders tutorial

[coachablekarma]

Hey guys, just trying to get reacquainted with melonJs so I am going through the space invaders tutorial.  I have hit a small roadblock at the adding lasers portion.  I am getting this error when I attempt to shoot.

Uncaught TypeError: Cannot read property 'width' of undefined melonJS.js:12328

at Class.init (melonJS.js:12328)
    at Class (melonJS.js:531)
    at Object.me.pool.api.pull (melonJS.js:4242)
    at Class.update (player.js:32)
    at Class.update (melonJS.js:12166)
    at Object.me.game.api.update [as _patched] (melonJS.js:2874)
    at Object.<anonymous> (debugPanel.js:291)
    at Object.defineProperty.value [as update] (melonJS.js:29274)
    at _renderFrame (melonJS.js:12856)

 

here is the js file for the player

game.Player = me.Sprite.extend({
    init : function()
    {
        var image = me.loader.getImage("player");
        this._super(me.Sprite, "init",
            [me.game.viewport.width / 2 - image.width / 2,
             me.game.viewport.height - image.height - 20,
             {image : image}
        ]);
        this.velx = 450;
        this.maxX = me.game.viewport.width - this.width;
    },
    
    update : function(time)
    {
        this._super(me.Sprite, "update", [time]);
            
        if (me.input.isKeyPressed("left"))
        {
            this.pos.x -= this.velx * time / 1000;
        }
        
        if (me.input.isKeyPressed("right"))
        {
            this.pos.x += this.velx * time / 1000;
        }
        
        this.pos.x = this.pos.x.clamp(0, this.maxX);
        
        if (me.input.isKeyPressed("shoot"))
        {
            me.game.world.addChild(me.pool.pull("laser", this.pos.x - game.Laser.width, this.pos.y - game.Laser.height));
        }
                
        return true;
        
    
    }
});

 

any help would be appreicated

Edited February 13, 2017 by coachablekarma
correction to script name

[Parasyte]

What does your "laser" class look like? If you copied from the tutorial directly, did you accidentally leave off the width and height properties? See the end of the code snippet for `game.Laser`: http://melonjs.github.io/tutorial-space-invaders/#part3

[coachablekarma]

Hey, thanks for the response.  I have those two values in the lasers class.  When I try to debug the game it is showing those values for the width and height.  Not sure why it is giving that error though.  I can post the lasers class as well as soon as I get to my PC.

[coachablekarma]

laser class:

 

game.Laser = me.Entity.extend({
    
    
    int : function (x,y)
    {

        this._super(me.Entity, "init", [x, y, {width: game.Laser.width, height: game.Laser.height}]);
        this.z = 5;
        this.body.setVelocity(0, 300);
        this.body.collisionType = me.collsion.types.PROJECTILE_OBJECT;
        this.renderable = new (me.Renderable.extend({
            init : function()
            {
                this._super(me.Renderable, "init", [0,0, game.Laser.width, game.Laser.height]);
            },
            destroy : function(){},
            draw : function (renderer)
            {
                var color = renderer.getColor();
                renderer.setColor('#5EFF7E');
                renderer.fillRect(0, 0, this.width, this.height);
                renderer.setColor(color);
            }
        }));
        this.alwaysUpdate = true;
    },
    
    update : function(time)
    {
        this.body.vel.y -= this.body.accel.y * time / 1000;
        if (this.pos.y + this.height <= 0)
        {
            me.game.world.removeChild(this);
        }
        
        this.body.update();
        me.collsion.check(this);
        
        return true;
    }
});

game.Laser.width = 5;
game.Laser.height = 28;

[Parasyte]

What version of melonJS are you using? I couldn't find any recent releases that lined up with the stack trace you provided. The current version is 4.1.0

[coachablekarma]

I'm using the 4.1.0 boilerplate 

[Parasyte]

Weird! I must have been building the wrong version, or looking at the wrong lines. The boilerplate is definitely on 4.1.0.

Ok, last question. How are you adding the laser class to the entity pool? The tutorial shows this:

me.pool.register("laser", game.Laser);

It appears that the call in player.js to me.pool.pull("laser", ...) is instantiating a me.Entity directly, instead of instantiating your game.Laser class. Just going entirely on the stack trace in your first post.

[coachablekarma]

I will take a look, and let you know